Apparatus fob casting



2. Sheets-Sheet 1 INV NTOR. I. 0MM/un .V .nvnng c. E. soRENsl-:N Er Al.

APPARATUS For: cAsTING Filed gept.

Jai; v'41,' 1938.

Jan. 4, 1938.v c. E. soRENEN Er Al. f. 2,104,406

APPARATUS FOR CASTING- Filed Sept. '7, 1935 2 Sheets-Sheet 2 4f c. f JM NVMENDRS :7 fw.

` `necessary in forming atented Jan. 4, 1938 PATENT OFFICE 2,104,406 APPARATUS FOR CASTING Charles E. Sorensen, Detroit,

and 'Russell H.

McCarroll, Dearborn, Mich., assignors .to Ford Motor Company, ration of Delaware Dearborn.. Mich., a corpo Application September "l, 1935, Serial No. 39,534 2 Claims.. (CL Zit- 209) 'The object of our invention is to provide a new method of forming castings, particularly engine cylinder block castings.

A further object of our invention is to provide a method of casting which will better equalize variations in composition andtemperature of the metal being cast, to thus produce more uniform castings. This is particularly advantageous where complicated castings are to be formed as it reduces the scrap to a large extent.

Still a further object of our invention is to provide a method o'f casting wherein the output of the-furnace which is used to heat the metal is almost doubled. 'Ihe commercial advantage `of this result is obvious.

Still a further object'of ourinvention is to provide a unique pouring ladle which is designed to be used in conjunction with a 'continuously moving conveyor system which supports the -molds for forming the castings.

Wlththese and other objects in view, our invention consists in the several steps which comprise our improved process, together with the apparatus used herein, as described in the specification, claimed in our claims and-illustrated inthe accompanying drawings, -in which:

l is a vertical central sectional view through an electric furnace and a holding furnace, both of which are used in carrying out our improved process.

Figure 2 is a plan `view of our improved ladle showing its relation to the holding-furnace, shown ,in Figure l.

Figure 3 is a` more detailed plan view of the pouring ladle showing its relation to the conveyor which supports the molds.

Figure 4 is a side elevation of the ladle which is shown in- Figures 2 and 3.

Figure 5 is an end view of the pouring ladle, and

Figure 6 is a vsectional View, taken onthe line 6 6 of Figure 3, l

In order to better appreciate the advantages of our improved process. it may be well to briefly describe the steps which have heretofore been cylinder block castings. The iron was rstheated to considerably above its melting temperature in either a cupola or an electric furnace and' then the molten iron was intermittently -poured from the furnace into ladles. These ladies were conveyed from the furnace to the molds in which the castings were to be formed. This conventional process has two disadvantages, the one being that the castings varied'considerably for the reason that the iron poured first from the ladle was considerably hotter than that poured from the bottom of the ladle. Furthermore, unavoidable variations in the time taken' to convey the several ladies from thefurnace to the molds also resulted in temperature variations. Where complicated iron castingsare to Vbe formed, it is very desirable to have the iron poured at a uniform temperature so that the structure of the iron in all castings will be similar.

A further disadvantage of the conventional process is that the furnace is idle all of the time the iron is being poured. When a fifteen ton electric furnace is used, it requires about twenty minutes to pour a batch of metal from the furnace intoA the ladles. Inasmuch as it requires "only twenty minutes to bring the charge up to the heat in such furnace, it is apparent that the furnace operates to heat the metal only half the time. Furthermore, pouring must be carried on intermittently with its resulting inefficiency. With our improved process not only is the pouring continuous, but the output of the electric furnace is almost double that possible with the conventional method of casting,

Briefly our improved process comprises melting the iron in an electric furnace and when it has attained its proper temperature pouring the contens of the furnace into a holding furnace. 'I'hls pouring operation only requires from one to two minutes. The holding furnace is constructed to have a normal capacity of about twice that of the electric furnace so that an equalization in the contents of successive batches from the electric furnace is obtained. A ,trough extends from the holding furnace through which a stream of metal continuously flows, this metal being deposited in a specially designed ladle. This ladle is mounted upon a dolly which moves back and forth along a short track. The molds are suspended from an overhead track and move along a path parallel to the track upon which the ladle moves. Thus. when the ladle is moving along `with one of the molds, the ladle may be tipped to flll the mold. The ladle is so constructed that the trough from the holding furnace continuously discharges metal into same.

The. apparatus for carrying out our improved process comprises a conventional fteen ton electric furnace III, this furnace being adapted to pivot around a fulcrum Il at one end thereof by means of a cable I2. The furnace is charged by pouring part cupola metal and part metal from the blast furnace into a trough I3, from which it ilows into the hearth of the furnace I0. When internal-combustion engine cylinder block castings are to be made, it has been found that using 70% of cupola iron to 30% of metal from the blast furnace results in excellent castings, the hot metal from the blast furnace alone being too high in carbon and silicon. After the metal in the furnace has-been heated for approximately twenty minutes, or to a temperature between 2700 and 2800 degrees F., the furnace is tipped around the fulcrum II so that the iron flows therefrom through a spout I4 into a trough I5 from which it flows through a port I6 into an air furnace I1. The furnace I1 has a capacity of thirty tons, having twice the capacity of the electric furnace I0. The metal in the air furnace is maintained at 2750 degrees F. by means of a coal flame which is directed into the furnace at one end thereof through an opening I8. The flame is directed against the bath so as to maintain same at the desired temperature. Because the furnace I1 has twice the capacity of the furnace AIl), it will be apparent that the device may be operated so that there is at least fteen tons of molten metal in the furnace I1 at all times.

The molds in which the castings are to be formed have been given the reference numeral I9 and are mounted between individual carriers 20 which are suspended from a conveyor chain 2I, the chain being supported from an I-beam 22 by means of a plurality of trolleys 23. 'I'he I-beam 22 and conveyor chain 2l form a. continuous conveyor system whereby the carriers 20 are conducted through a loading room wherein the molds I9 are placed thereon and then conducted along a path adjacent to the furnace I1 where the molds are poured. The molds are then conveyed toa dumping rack and then the carriers return to the loading room.

Y In order to pour the iron from the furnace I1 into the molds I9, we have provided a reciprocating ladle which is adapted to travel along with each mold during a portion of its travel adjacent to the furnace. A pair of parallel tracks 24 are secured to the floor and the dolly 25 is mounted to travel back and forth along this track. An electric motor 26 drives the dolly 25 in both directions. A pair of supports 21 extend upwardly from the dolly 25, each support having a bearing in its upper portion in which a pair of trunnions 28 are rotatably mounted. These trunnions project horizontally from the respective ends of a ladle 29.V It will be noted from Figure 5 that the trunnions 28 are disposed directly above the molds I9. A sector gear 30 is fixed to one of the trunnions 28 which gear is in mesh with a pinion 3|. The pinion 3| is driven by a hand wheel 32 through a speed reducing gearing mechanism 33 so that, when the hand wheel is rotated in one direction, the ladle Will be tilted up to the position shown by dotted lines 34 in Figure 5. At this time the metal in the ladle will ow out through a spout 35, and into one of the molds there beneath. Suitable arms 31 extend from the respective ends of the trunnions 28, and a compression spring 38 extends between the free end of each arm 31 and the base of the dolly 25. This spring is loaded to such an extent that it counteraets the weight of the ladle and metal therein to a large extent. Inasmuch as the trunnions 28 are towards the top and to the extreme left hand side of the dolly 25, the device is materially offset so that it would be quite diiiicult for the operator to tip the ladle if it were not for the counterbalancing duc to the springs 38. A very important feature of this arrangement is that the spout 35 is disposed in axial alignment with the trunnions 28 so that when the ladle is tipped the relative positions of the spout and mold do not change.

It will be noted that a trough 36 extends from the furnace I1 to position over the ladle 29, the trough being'parallel to the track 24. The ladle is sufficiently long that the trough 3 6 is always positioned above same so that metal 'flowing therethrough will be deposited in the ladle irrespective of the position of the ladle and dolly 25 upon the track 24. Referring to Figures 2 and 6, it will be noted that the ladle 29 is provided with a partition- 40 there across near the spout 35, the purpose of which is to keep slag from flowing out of this spout. The partition does not extend to the bottom of the ladle so that the metal is free to flow from one side of the ladle to the other, flowing beneath the partition. Consequently, slag which forms upon the surface of the metal at the receiving end of the ladle is not permitted to flow beyond the partition 40.

In carrying out our process molten iron is charged into the electric furnace I0 and is heated therein for about twenty minutes. 'I'he furnace I0 is then quickly discharged into the holding furnace I1 and a new charge of metal placed in the electric furnace I0. Before starting to draw from the holding furnace, it is desirable that a second batch of iron from the furnace I 0 be mixed with the first batch in the holding furnace to equalize the temperature and composition of successive charges from the electric furnace. When it is desired to start the pouring operation, the holding furnace is tapped so that metal flows therefrom through the trough 36 into the ladle 29. A diameter outlet opening in the holding furnace is just about sufficient to keep up with a fifteen ton electric furnace. The metal flows continuously through the trough 36 and discharges into the ladle 29. After the ladle has become one half to two thirds full, the operator aligns the -spout 35 with one of the moving molds and starts the motor 26 which conveys the dolly 25 at the same speed as the mold. The ladle is then tipped so that metal flows out through the spout 35 into the adjacent mold. As soon as the mold has become filled the ladle is dropped bacl to its level position and the motor 26'reversed to bring the dolly 25 back to its original starting position. The molds I9 are so spaced that, when the dolly is returned to its starting position, it will be aligned with the next mold on the conveyor so that the ladle may be immediately tipped tc ll this mold while it is traveling towards the furnace. The novel feature of this process is that, during the travel of the ladle 29 in both directions, the metal is flowing continuously through the trough 36. In casting cylinder block: a conveyor speed of eight and one half feet pei minute has been found desirable where the mold: are spaced at five foot intervals along the conveyor chain.

Among the many advantages arising from th use of our improved process, it may be well t4 mention that the output of the electric furnaci is substantially doubled inasmuch as the furnac1 may be emptied in the matter of a. minute or two whereas with the older methods of casting, when the iron was poured into individual ladies, a timi equivalent to the heating time was required t4 empty the furnace.

Furthermore, the composition of successiw charges from the electrical furnaceis equalize so that more uniform castings result.

deposited in said ladle, said metering jet being of Furthermore, as the temperature of the holding furnace may be maintained at within very close limits more uniform castings result. While a loss of heat in the trough 36 and ladle 29 is inevitable, the metal dropping to 2650 degrees F.

- as it flows therethrough, still this drop is uniform and can therefore be compensated for in the heating of the holding furnace so that a pouring temperature Within very close limits is always assured.

Some changes may be made in the various steps comprising our improved process and apparatus therefor without departing from the spirit of our invention and it is our intention to cover by our claims such changes as may reasonably be included within the scope thereof.

We claim as our invention:

1. In combination, an electric furnace, a closed type holding furnace of substantially twice the capacity of said electric furnace, a ladle, aplurality of molds, means for mixing successive l batches from said electric furnace in said holding furnace, means associated with said holding furnace for adding heat to said me'tal to maintain same at a uniform temperature substantially above its melting temperature, a trough extending between said holding furnace and said ladle, a fixed metering jet disposed betweenl said holding furnace and said trough whereby metalis continuously drawn from said holding furnace and such size that a quantity of metal equivalent to one of said batches will be deposited in said ladlein the time taken to heat -and pour said batch, means for conveying molds continuously past said ladle, means for reciprocating said ladle in a pathvparallel to thepath of said molds and at a similar speed whereby each of 'the molds will r'emain fixed relative to said ladle during one stroke of its reciprocating movement, and means for pouring metal from said ladle into, the adjacent mold during said fixed portion of each stroke.

2. In combination Ya l5-ton electric furnace, a 30ton' holding furnace, a ladle, a plurality of molds, means for intermittently heating metal in said electric furnace to a temperature betweenv 2700* F. and 2800 F., said metal after heating being mixed in said holding furnace, means for adding heat to said holding furnace so as to maintain the metal therein at substantially 27.50 F., a trough extending between said holding furnace and said ladle, said holding furnace having a diameter outlet jet therein through which metal continuously flows from said furnace into said ladle through said trough, and means for conveying molds continuously past said ladle, and means for intermittently pouring metal from said ladle into said molds.

CHAS. E. SORENSEN.

RUSSELL H.`McCARRIL. 

